package top.yuan67.demo;

import org.springframework.cache.annotation.CachingConfigurerSupport;
import org.springframework.cache.annotation.EnableCaching;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.data.redis.serializer.StringRedisSerializer;

/**
 * redis配置
 */
@Configuration
@EnableCaching
public class RedisConfig extends CachingConfigurerSupport {
  @Bean
  @SuppressWarnings(value = {"unchecked", "rawtypes"})
  public RedisTemplate<Object, Object> redisTemplate(RedisConnectionFactory connectionFactory) {
    RedisTemplate<Object, Object> template = new RedisTemplate<>();
    template.setConnectionFactory(connectionFactory);
    
    FastJson2JsonRedisSerializer serializer = new FastJson2JsonRedisSerializer(Object.class);
    
    // 使用StringRedisSerializer来序列化和反序列化redis的key值
    template.setKeySerializer(new StringRedisSerializer());
    template.setValueSerializer(serializer);
    
    // Hash的key也采用StringRedisSerializer的序列化方式
    template.setHashKeySerializer(new StringRedisSerializer());
    template.setHashValueSerializer(serializer);
    
    template.afterPropertiesSet();
    return template;
  }
  
  @Bean
  public DefaultRedisScript<Long> limitScript() {
    DefaultRedisScript<Long> redisScript = new DefaultRedisScript<>();
    redisScript.setScriptText(limitScriptText());
    redisScript.setResultType(Long.class);
    return redisScript;
  }
  
  /**
   * 限流脚本
   */
  private String limitScriptText() {
    return "local key = KEYS[1]\n" +
        "local count = tonumber(ARGV[1])\n" +
        "local time = tonumber(ARGV[2])\n" +
        "local current = redis.call('get', key);\n" +
        "if current and tonumber(current) > count then\n" +
        "    return tonumber(current);\n" +
        "end\n" +
        "current = redis.call('incr', key)\n" +
        "if tonumber(current) == 1 then\n" +
        "    redis.call('expire', key, time)\n" +
        "end\n" +
        "return tonumber(current);";
  }
}
